Merge "Revert^2 "Update the BackgroundThread dependency"" into main

import android.util.ArrayMap;

import android.util.ArraySet;

import android.util.AtomicFile;

import android.util.BackgroundThread;

import android.util.LongArrayQueue;

import android.util.Slog;

import android.util.Xml;

import com.android.internal.annotations.GuardedBy;

import com.android.internal.annotations.VisibleForTesting;

import com.android.internal.os.BackgroundThread;

import com.android.internal.util.IndentingPrintWriter;

import com.android.internal.util.XmlUtils;

import com.android.modules.utils.TypedXmlPullParser;

/*

 *  * Copyright (C) 2024 The Android Open Source Project

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package android.util;

import android.annotation.NonNull;

import android.os.Handler;

import android.os.HandlerThread;

import com.android.internal.annotations.GuardedBy;

import java.util.concurrent.Executor;

/**

 * Thread for asynchronous event processing. This thread is configured as

 * {@link android.os.Process#THREAD_PRIORITY_BACKGROUND}, which means fewer CPU

 * resources will be dedicated to it, and it will "have less chance of impacting

 * the responsiveness of the user interface."

 * <p>

 * This thread is best suited for tasks that the user is not actively waiting

 * for, or for tasks that the user expects to be executed eventually.

 *

 * @see com.android.internal.os.BackgroundThread

 *

 * TODO: b/326916057 depend on modules-utils-backgroundthread instead

 * @hide

 */

public final class BackgroundThread extends HandlerThread {

    private static final Object sLock = new Object();

    @GuardedBy("sLock")

    private static BackgroundThread sInstance;

    @GuardedBy("sLock")

    private static Handler sHandler;

    @GuardedBy("sLock")

    private static HandlerExecutor sHandlerExecutor;

    private BackgroundThread() {

        super(BackgroundThread.class.getName(), android.os.Process.THREAD_PRIORITY_BACKGROUND);

    }

    @GuardedBy("sLock")

    private static void ensureThreadLocked() {

        if (sInstance == null) {

            sInstance = new BackgroundThread();

            sInstance.start();

            sHandler = new Handler(sInstance.getLooper());

            sHandlerExecutor = new HandlerExecutor(sHandler);

        }

    }

    /**

     * Get the singleton instance of this class.

     *

     * @return the singleton instance of this class

     */

    @NonNull

    public static BackgroundThread get() {

        synchronized (sLock) {

            ensureThreadLocked();

            return sInstance;

        }

    }

    /**

     * Get the singleton {@link Handler} for this class.

     *

     * @return the singleton {@link Handler} for this class.

     */

    @NonNull

    public static Handler getHandler() {

        synchronized (sLock) {

            ensureThreadLocked();

            return sHandler;

        }

    }

    /**

     * Get the singleton {@link Executor} for this class.

     *

     * @return the singleton {@link Executor} for this class.

     */

    @NonNull

    public static Executor getExecutor() {

        synchronized (sLock) {

            ensureThreadLocked();

            return sHandlerExecutor;

        }

    }

}

/*

 * Copyright (C) 2024 The Android Open Source Project

 *

 * Licensed under the Apache License, Version 2.0 (the "License");

 * you may not use this file except in compliance with the License.

 * You may obtain a copy of the License at

 *

 *      http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package android.util;

import android.annotation.NonNull;

import android.os.Handler;

import java.util.Objects;

import java.util.concurrent.Executor;

import java.util.concurrent.RejectedExecutionException;

/**

 * An adapter {@link Executor} that posts all executed tasks onto the given

 * {@link Handler}.

 *

 * TODO: b/326916057 depend on modules-utils-backgroundthread instead

 * @hide

 */

public class HandlerExecutor implements Executor {

    private final Handler mHandler;

    public HandlerExecutor(@NonNull Handler handler) {

        mHandler = Objects.requireNonNull(handler);

    }

    @Override

    public void execute(Runnable command) {

        if (!mHandler.post(command)) {

            throw new RejectedExecutionException(mHandler + " is shutting down");

        }

    }

}